Belly Weight Predicts Heart Health Better Than BMI, Study Indicates

Key Takeaways: 

• Fat stored around the waist is a stronger predictor of heart disease than body mass index alone.
  
• People with preclinical obesity face a raised cardiovascular risk despite appearing healthy.
  
• Researchers estimate early intervention could prevent 45% of new cardiovascular disease cases.
  
  
  

Why waist size matters more than the scales

People living with overweight or obesity can carry a higher risk of heart disease even when they appear to be perfectly healthy, according to new research presented at the International Congress on Obesity in Mexico City (15–17 July). Combining waist-based measurements with body mass index (BMI) to detect this hidden risk and act early could, over the years ahead, prevent hundreds of thousands of people from dying from heart attacks, strokes and other cardiac problems, researchers from the University of Glasgow, Glasgow, UK, said.

“We know that excess weight, particularly around the waist, increases the risk of heart disease,” said lead researcher Estefania Fuentes Avalos. “In 2021, an estimated 1.9 million cardiovascular disease deaths – almost one in 10 heart-related deaths worldwide – were attributed to high body mass index.

“The link between central, or abdominal, obesity and heart disease is especially strong because fat stored around the waist, known as visceral fat, is metabolically active and releases inflammatory substances into the bloodstream. Over time, this chronic inflammatory state can damage blood vessels and accelerate the buildup of arterial plaque, significantly increasing the risk of heart attacks.”

The limits of BMI

BMI, a measure of weight compared with height, is routinely used to assess a person’s weight status, defining whether they have a normal weight, overweight or obesity. However, it does not take into account where fat is stored in the body.

To address this and other shortcomings of BMI, The Lancet Diabetes & Endocrinology Commission recently proposed a different way of assessing obesity status. The Lancet Commission framework uses BMI together with central adiposity markers – waist measurements – to determine whether a person has excess body fat. People with excess body fat are then categorised as having either preclinical obesity or clinical obesity, depending on whether they also have long-term obesity-related conditions such as high blood pressure, joint pain and sleep apnoea.

The new study set out to establish whether this method is better at identifying people at high risk of cardiovascular disease than BMI alone.

“Detecting cardiovascular risk at an early stage is essential, particularly at the preclinical stage of obesity, as it provides a window of opportunity to implement timely, targeted interventions before obesity-related complications such as high blood pressure arise,” Fuentes Avalos said.

“This underpins our focus on risk stratification in this group, with the aim of detecting high-risk individuals who may otherwise be overlooked.”

What the study looked at

Fuentes Avalos examined data on 382,769 adults of white ethnicity in the UK Biobank study (age range 40–69 years, average age 56 years, 53% women).

Under The Lancet Commission framework, 285,190 (74%) of the participants had excess body fat, based on BMI and central adiposity markers. Within this group, 102,237 (26.7%) were classified as having preclinical obesity – excess body fat without long-term obesity-related conditions – and 182,953 (47.8%) as having clinical obesity, meaning excess body fat alongside long-term obesity-related conditions. The remainder had neither excess body fat nor long-term obesity-related conditions; they were classified as not having obesity and served as the reference group.

None of the participants had cardiovascular disease at the start of the study. Hospital and death records provided information about diagnoses of, and deaths from, heart attacks, strokes and other forms of cardiovascular disease over the following 12 years. During this time, there were 41,742 new cases of, and 8,832 deaths from, cardiovascular disease. Studies of this scale underline how much practical assessment skill clinicians need when supporting patients with excess weight – a competency CCH’s Obesity Essentials short course is designed to build.

Clinical obesity carried the sharpest risk

Analysis of the data showed that people with clinical obesity were far more likely to develop, or die from, cardiovascular disease than those without obesity.

Women with clinical obesity developed cardiovascular disease at a rate 2.5-fold higher than women without obesity, and died from it at an almost threefold (2.8-fold) higher rate. Men with clinical obesity developed cardiovascular disease at an almost twofold higher rate (1.9-fold) and had a 2.6-fold higher rate of cardiovascular death than men without obesity.

The hidden risk in preclinical obesity

People with preclinical obesity were also at greater risk, despite having no obesity-related conditions and appearing to be in good health.

Women with preclinical obesity developed cardiovascular disease at a 38% higher rate and died from it at a 46% higher rate than women without obesity. For men, preclinical obesity was associated with an 18% higher rate of developing cardiovascular disease and a 52% higher rate of cardiovascular death.

All of the results were adjusted for socioeconomic status and lifestyle factors, including smoking and alcohol consumption.

More waist markers, more risk

Further analysis showed that the more high-risk central adiposity markers a person had, the more likely they were to develop heart disease. For example, a woman with one high-risk marker – waist circumference, waist-to-hip ratio or waist-to-height ratio – was 17% more likely to develop cardiovascular disease than a woman with no high-risk waist measurements. Having all three high-risk measurements increased the risk by 64%. The study also found that waist measurements were more accurate at predicting cardiovascular disease than BMI.

A window of opportunity

The researchers concluded that people with preclinical obesity are at higher risk of developing, and dying from, cardiovascular disease despite appearing to be healthy.

“Preclinical obesity is a critical window of opportunity to improve heart health. Routinely measuring waist circumference, waist-to-hip ratio and waist-to-height ratio along with BMI would identify high-risk individuals who might be overlooked by assessing BMI alone,” Fuentes Avalos said.

“They could then be offered intensive diet and exercise programs to improve their cardiac and overall health.

“We have calculated that early intervention could prevent 45% of new cases of cardiovascular disease and 41% of cardiovascular disease deaths in similar populations.

“Given that cardiovascular disease remains a leading cause of ill health and death globally, routinely taking waist measurements along with BMI could prevent hundreds of thousands of deaths over a decade alone.”

CCH insight

Findings like these are only useful in practice if clinicians feel confident assessing excess weight and having sensitive, evidence-based conversations with patients about it. CCH’s Obesity Essentials – an online CPD short course offering 10 CPD hours – equips healthcare professionals with the practical skills to assess and manage patients living with overweight and obesity, from measurement through to compassionate communication. Explore Obesity Essentials and strengthen your day-to-day weight-management practice.